1. Field of the Invention
The present invention relates to a system and method for wireless communication between mobile transceivers and wireless infrastructure elements through the use of intermediary mobile transceivers having store-and-forward message passing capabilities. Specifically, the present invention relates to a system and method for providing communication between mobile wireless transceivers and wireless infrastructure elements beyond the coverage of wireless infrastructure elements through the use of direct transceiver to transceiver communication.
2. Description of the Related Art
In recent years, a type of mobile communications network known as an xe2x80x9cad-hocxe2x80x9d network has been developed for use by the military. In this type of network, each user terminal (hereinafter xe2x80x9cmobile nodexe2x80x9d) is capable of operating as a base station or router for the other mobile nodes, thus eliminating the need for a fixed infrastructure of base stations. Accordingly, data packets being sent from a source mobile node to a destination mobile node are typically routed through a number of intermediate mobile nodes before reaching the destination mobile node. Details of an ad-hoc network are set forth in U.S. Pat. No. 5,943,322 to Mayor, the entire content of which is incorporated herein by reference.
More sophisticated ad-hoc networks are also being developed which, in addition to enabling mobile nodes to communicate with each other as in a conventional ad-hoc network, further enable the mobile nodes to access a fixed network and thus communicate with other types of user terminals, such as those on the public switched telephone network (PSTN) and on other networks such as the Internet. Details of these types of ad-hoc networks are described in U.S. patent application Ser. No. 09/897,790 entitled xe2x80x9cAd Hoc Peer-to-Peer Mobile Radio Access System Interfaced to the PSTN and Cellular Networksxe2x80x9d, filed on Jun. 29, 2001, in U.S. patent application Ser. No. 09/815,157 entitled xe2x80x9cTime Division Protocol for an Ad-Hoc, Peer-to-Peer Radio Network Having Coordinating Channel Access to Shared Parallel Data Channels with Separate Reservation Channelxe2x80x9d, filed on Mar. 22, 2001, and in U.S. patent application Ser. No. 09/815,164 entitled xe2x80x9cPrioritized-Routing for an Ad-Hoc, Peer-to-Peer, Mobile Radio Access Systemxe2x80x9d, filed on Mar. 22, 2001, the entire content of each said patent application being incorporated herein by reference.
However, in current wireless systems designed to support mobile subscribers, the subscriber may only communicate with another subscriber through the network""s traditional infrastructure elements. Cellular networks, such as the Analog Mobile Phone System, Time Division Multiple Access (TDMA) or Code Division Multiple Access (CDMA) cellular systems, Personal Communication Systems (PCSs), or other cellular and data networks, such as Metricom""s data network and the former Ardis network, only allow subscriber communication with another subscriber through the network""s infrastructure. Subscribers to the service provided by such mobile communication systems cannot communicate directly with one another using their subscriber radios or cellular telephones and therefore, need to be within range of an infrastructure element such as a base station or wired access point. Unfortunately therefore, the subscriber""s ability to communicate is limited to geographical areas having such infrastructure equipment coverage.
Other wireless communication systems, such as wireless local area networks (LANs) and, in particular, 802.11 wireless LANs, have a peer-to-peer mode that enables subscriber equipment, such as Personal Computer Memory Card International Association standard (PCMCIA) card radios, to communicate directly with one another, without any infrastructure equipment, such as an access point. However, these communication systems are not designed to support mobile (i.e. vehicle based) users. The radios of such systems are typically designed to provide high throughput in an office or campus environment with little processing gain or range. They typically are not capable of providing the Doppler offsets that are found in radios traveling at highway speeds. Furthermore, these communication systems have no provision for special protocol that can provide a xe2x80x9cstore-and-forwardxe2x80x9d message-passing capability that is initiated in peer-to-peer communication and completed when the second peer arrives within range of infrastructure elements.
Moreover, in mobile wireless systems, there is no way to hand off messages without infrastructure elements. In wireless LAN systems, there is neither support for mobile subscribers, nor protocol that provides for the special classes of message that can be handled in a special manner.
Therefore, a need exists for a system and method of communication in which mobile subscribers may communicate directly with one another beyond infrastructure equipment coverage, and which includes protocol to provide store-and-forward message-passing capability that is initiated in peer-to-peer communication and completed when the storing peer arrives within infrastructure coverage to pass the stored information to the infrastructure.
An object of the present invention is to provide a system and method of peer-to-peer and peer-to-peer-to-infrastructure store-and-forward communication capabilities between communication subscribers in a communication network.
Another object of the present invention is to provide a system and method of peer-to-peer communication that is capable of providing appropriate Doppler offsets to enable peer-to-peer communications between highly mobile communication subscribers.
A further object of the present invention is to provide a protocol through which information communicated between mobile subscribers in peer-to-peer communication may be stored and later forwarded to a destination through wireless infrastructure elements when detected by the mobile subscriber that is storing the information.
These and other objects are substantially achieved by providing a system and method for sending and receiving status and request-for-help messages automatically between mobile host computers and transceivers and ultimately, to an appropriate destination via a wireless infrastructure. When wireless infrastructure coverage is not available, a host computer and transceiver will communicate the necessary information to a wireless infrastructure via a passing mobile host computer and transceiver located, for instance, in a vehicle. In this case, the message would be stored in the passing mobile host computer and transceiver until they are within range of infrastructure coverage, and then transmitted from that mobile host computer and transceiver through wireless infrastructure equipment to an appropriate destination.